Lubrication is forced throughout, the oil being
The whole of the camshaft and valve gear is totally
enclosed by an extension of the water jacket, and is drawn from the sump and forced by a gear pump,
constantly sprayed with oil. At the driven end of driven off the water pump shaft, through passages
the camshaft is a small air pump, operated by a ball- formed in the crankcase to all the crankshaft bearings
and through the hollow crankshaft to
bearing eccentric, which supplies air
the big ends, thence up the connecting
pressure for the petrol feed.
rods to the gudgeon pins. Ducts also
The pistons are of " Aloyanum," an
lead oil from the main passage to the
aluminium alloy having an ultimate
cylinder walls, whilst oil is delivered to
strength of about 18 tons per sq. in.,
the cams and camshaft by way of a
and each weigh i f lbs. They are
pipe at the end of the engine. Oil
fitted with two Burd high compression
from the camshaft case drains back to
rings, and grooves are formed on the
the crankcase through a larger pipe,
lower portion of the walls. The conwithin which is the feed pipe just
necting rods are I section made from
referred to, and also down the tube
chrome vanadium steel, the tensile
containing the vertical shaft driving
strength of which, when heat treated,
the camshaft. All the gears are thus
is ioo tons per sq. in. Seven main
well
lubricated. Before passing from
bearings support the crankshaft, whilst
the
crankcase
to the sump the oil flows
the thrust, in either direction, is taken
through a cooling radiator, which will
by a double row Heso-Bright ballbe seen at the bottom of the crankcase
bearing mounted next to the propeller.
in the accompanying illustrations. A
This latter bearing may easily be S k e t c h of t h e p i s t o n a n d
r
i
n
g
of
t
h
e
120
h
.
p
.
by-pass at the side of the crankcase
adjusted by removing the lower porC h r i s t o ff e r s o n a e r o
enables the oil pressure to be regulated
tion of the crankcase end. Each main
engine.
from 10 to ioo lbs. A double Miller
bearing is 2\ ins. diameter. Quite an
important feature consists of the propeller flange, or Zenith carburettor is fitted, the mixture being
which can be detached from the motor with the conveyed to the cylinders by the curious loopgreatest of ease. The crankcase is of Aloyanum, form induction pipe shown in the side view. The
and is horizontally divided so that when removed weight of this engine complete, but not including
the crankshaft is easy of access. The cooling water exhaust pipe and propeller flange, is 5 i i £ lbs., giving
is circulated by a centrifugal pump driven off the a weight per h.p. at 1,400 r.p.m. of 4-26 lbs.
end of the crankshaft.
Tested last May by the technical committee of the
Ignition is by two Bosch magnetos driven off the Automobile Club of America, one of these engines gave
lower bevel of the vertical shaft that drives the cam- the following results :—The test for h.p., fuel conshaft. There are two plugs to each cylinder, and sumption, &c, showed that 96-5 h.p. was developed
these are located immediately under the valves.
at 1,199 r.p.m , 113 h.p. at 1,390 r.p.m., and 130*9 h.p.
at 1,655 r.p.m., the fuel consumption
at these speeds being "68, "68, and '64 lb.
per h.p. hour. The average speed
during the 5 hrs. 15 mins. running was
1,449 r -P m -> the average h.p. 1136,
and the average petrol consumption
was 9 4 gals, per hour.
***•
^1 H^Sr^n^ •
T h r e e - q u a r t e r a n d end views of t h e l a t e s t 120 h . p . Christofferson
aero engine.
IO92
^m
K^^
T h e o v e r h e a d c a m s h a f t a n d valves of
t h e l a t e s t 120 h . p . Christofferson a e r o
engine.